An FSK demodulator for Bluetooth applications having no external components

An injection-locked oscillator in combination with a phase detector is shown to make a very effective FSK demodulator for Bluetooth applications. The dynamic behavior allows automatic tuning from outside the locking range. Two tuning methods are described which eliminate the need for external components. A cancellation technique is used which minimizes filtering requirements. The demodulator was fabricated in a 0.4 /spl mu/m BiCMOS technology.